Cutting out the medical blunders

The cervical screening programme now has tough checks

Ministers are wondering how medical errors can be reduced - but a successful way of tackling them exists already.

Although pathologist Dr James Elwood - attacked for making more than 200 errors over a four year period - had a better than average error rate, his case illustrates weaknesses in the way that many doctors are monitored.

The hospital where he worked has admitted not auditing any of his work throughout that period, which meant that when concerns were raised a huge number of samples had to be rechecked.

Histopathology, Dr Elwood's speciality, is only beginning to adopt some of the checks and balances adopted by the NHS's own cancer screening programmes over the last five years.

Series of scandals

The cervical screening programme was struck by a series of scandals in the late 1980s and early 1990s, culminating in a complete breakdown of the service at the Kent and Canterbury Hospital.

When the errors came to light in 1994, 90,000 smears had to be re-examined, and a subsequent inquiry concluded that eight women had died as a result

Thirty more had undergone hysterectomies because their disease had not been spotted earlier.

Although efforts to improve quality had been underway before 1994, the scandal added momentum to reforming efforts.

A rigorous programme of quality assurance and accreditation began to force the worst laboratories to improve, and while bosses at the programme say that preventing all errors is simply impossible, they are more likely to pick up problems early.

Julietta Patnick, the programme's director, said: "In the late 1980s, there was a proficiency test for screeners, but this wasn't even compulsory.

"The scandal at Kent and Canterbury gave us added teeth, and allowed us to bring in mandatory accreditation."

Smear slides can be hard to read

She says that individual laboratories have found themselves removed from the programme, although this is normally a short-term measure which helps "concentrate the minds" of managers to get things right.

And although chronic staff shortages still create pressures which can lead to mistakes in laboratories, in terms of checks, the cervical screening programme is still streets ahead of many ordinary hospital labs, which check samples for signs of various diseases, including cancer.

And technology is about to take the programme even further ahead.

New technique

Government advisors, the National Institute for Clinical Excellence, gave the go-ahead this week for the first pilot studies of a new technique, called liquid-based cytology (LBC).

This promises to cut the error rate even further, and perhaps even to allow the introduction of computerised screening at some future point.

A smear test, or pap test, involves scraping a tiny sample of cells from various points of a woman's cervix - the neck of the womb.

These are literally smeared onto a microscope slide, which is then examined for the cells which look different because they are in the early stages of changing into cancer cells.

However, the technique has its limitations - which can lead both to pre-cancerous cells being missed and women being unnecessarily called back to have another smear taken.

For example, because of the technique, the cells looked at on the slide may have come only from one of the parts of the cervix - and rogue cells elsewhere may not be viewed.

In addition, additional debris and blood on the slide may obscure the view the screener has of the cells.

LBC takes the cells from the woman in exactly the same way, but, instead of smearing them out on a slide, they are stored in a solution and then filtered out in the lab.

When these cells are then examined under the microscope, they are free of debris, and include cells from all parts of the cervix.

Extra screening tests

Because the view is clearer, the possibilities for automation are much higher.

There is another bonus - LBC means there is a sample left over after screening which can be used for another purpose.

This might include additional screening for the human papillomavirus - a virus generally considered to play a role in causing cervical cancer in some of the women who carry it.

And the lab could even carry out a test for chlamydia - a sexually-transmitted infection which, although symptomless in women, can lead to infertility in some cases.